Display device

ABSTRACT

Disclosed is a display device. The display device includes: a light source; a light guide plate into which light is incident from the light source; a light conversion member on the light guide plate; and a display panel on the light conversion member, wherein a plurality of scattering parts having a diameter in a range of 90 μm to 300 μm are provided in the light guide plate.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is a U.S National Stage Application under 35 U.S.C.§371 of PCT Application No. PCT/KR2012/009995, filed Nov. 23, 2012,which claims priority to Korean Patent Application No. 10-2011-0131365,filed Dec. 8, 2011, whose entire disclosures are hereby incorporated byreference.

TECHNICAL FIELD

The embodiment relates to an optical member and a display device havingthe same.

BACKGROUND ART

Recently, flat display devices, such as an LCD (liquid crystal display),a PDA (plasma display panel) or an OLED (organic light emitting diode),have been increasingly developed instead of conventional CRTs (cathoderay tubes).

Among them, the LCD includes a liquid crystal display panel having athin film transistor substrate, a color filter substrate and a liquidcrystal injected between the thin film transistor substrate and thecolor filter substrate. Since the liquid crystal display panel is anon-emissive device, a backlight unit is provided below the thin filmtransistor substrate to supply light. Transmittance of the light emittedfrom the backlight unit is adjusted according to the alignment state ofthe liquid crystal.

The backlight unit is classified into an edge-illumination typebacklight unit and a direct-illumination type backlight unit accordingto the position of a light source. According to the edge-illuminationtype backlight unit, the light source is located at a side of a lightguide plate.

The direct-illumination type backlight unit has been developed as thesize of the LCD has become enlarged. According to thedirect-illumination type backlight unit, at least one light source islocated below the liquid crystal display panel to supply the light overthe whole area of the liquid crystal display panel.

When comparing with the edge-illumination type backlight unit, thedirect-illumination type backlight unit can employ a large number oflight sources so that the high brightness can be achieved. In contrast,the direct-illumination type backlight unit must have thickness largerthan thickness of the edge-illumination type backlight unit in order toensure brightness uniformity.

In order to solve the above problem, a quantum dot bar having aplurality of quantum dots, which can convert blue light into red lightor green light, is positioned in front of a blue LED that emits the bluelight. Thus, as the blue light is irradiated onto the quantum dot bar,the blue light, the red light and the green light are mixed with eachother by the quantum dots distributed in the quantum dot bar and themixed light is incident into the light guide plate, so that white lightis generated.

If the white light is supplied to the light guide plate by using thequantum dot bar, high color reproduction may be realized.

The backlight unit may include an FPCB (flexible printed circuit board)provided at one side of the blue LED, which generates blue light, tosupply signals and power to the LED and a bonding member formed underthe bottom surface of the FPCB.

The display device capable of displaying various images using the whitelight supplied to the light guide plate through the quantum dot bar asthe blue light is emitted from the blue LED has been extensively used.

The display device employing the quantum dots is disclosed in KoreanUnexamined Patent Publication No. 10-2011-0068110.

DISCLOSURE OF INVENTION Technical Problem

The embodiment provides a display device representing improvedbrightness.

Solution to Problem

According to the embodiment, there is provided a display deviceincluding: a light source; a light guide plate into which light isincident from the light source; a light conversion member on the lightguide plate; and a display panel on the light conversion member, whereina plurality of scattering parts having a diameter in a range of 90 μm to300 μm are provided in the light guide plate.

According to the embodiment, there is provided a display deviceincluding a light guide plate; a light source in a side of the lightguide plate; a light conversion sheet on the light guide plate, and adisplay panel on the light conversion sheet, wherein the light guideplate comprises scattering parts having a diameter in a range of 90 μmto 300 μm.

Advantageous Effects of Invention

In the display device according to the embodiment, the light conversionmember is provided on the light guide plate, and the scattering partshave a large diameter in the range of 90 μm to 300 μm. In this case, thelight conversion member includes light conversion particles. The lightconversion particles can randomly change a light path while converting awavelength of incident light. That is, the light conversion particlescan perform a scattering function.

Accordingly, even if the scattering parts have a large diameter, thelight conversion member has a scattering function so that the brightnessuniformity is not reduced.

Consequently, the scattering parts have a large diameter so that thebrightness can be improved.

As a result, the display device according to the embodiment canrepresent improved brightness without reducing brightness uniformity.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an exploded perspective view showing a liquid crystal displayaccording to the embodiment;

FIG. 2 is a perspective view showing a light guide plate;

FIG. 3 is a sectional view taken along line A-A′ of FIG. 2;

FIG. 4 is a sectional view showing the light guide plate;

FIG. 5 is a sectional view showing a light guide plate according toanother embodiment;

FIG. 6 is a sectional view showing a light guide plate according tostill another embodiment;

FIG. 7 is a perspective view showing the light guide plate according tostill another embodiment;

FIG. 8 is a sectional view taken along line B-B′ of FIG. 7;

FIG. 9 is a perspective view showing a light conversion sheet accordingto the embodiment;

FIG. 10 is a sectional view taken along line C-C′ of FIG. 9.

MODE FOR THE INVENTION

In the description of the embodiments, it will be understood that, whena substrate, a frame, a sheet, a layer, or a pattern is referred to asbeing “on” or “under” another substrate, another frame, another sheet,another layer, or another pattern, it can be “directly” or “indirectly”on the other substrate, frame, sheet, layer, or pattern, one or moreintervening layers may also be present. Such a position of each elementhas been described with reference to the drawings. The thickness andsize of each element shown in the drawings may be exaggerated, omittedor schematically drawn for the purpose of convenience or clarity. Inaddition, the size of elements does not utterly reflect an actual size.

FIG. 1 is an exploded perspective view showing a liquid crystal displayaccording to the embodiment. FIG. 2 is a perspective view showing alight guide plate. FIG. 3 is a sectional view taken along line A-A′ ofFIG. 2. FIG. 4 is a sectional view showing the light guide plate. FIG. 5is a sectional view showing a light guide plate according to anotherembodiment. FIG. 6 is a sectional view showing a light guide plateaccording to still another embodiment. FIG. 7 is a perspective viewshowing the light guide plate according to still another embodiment.FIG. 8 is a sectional view taken along line B-B′ of FIG. 7. FIG. 9 is aperspective view showing a light conversion sheet according to theembodiment. FIG. 10 is a sectional view taken along line C-C′ of FIG. 9.

Referring to FIGS. 1 to 10, the liquid crystal display according to theembodiment includes a backlight unit 10 and a liquid crystal panel 20.

The backlight unit 10 supplies light to the liquid crystal panel 30. Thebacklight unit 10 serves as a surface light source so that the light canbe uniformly supplied to a bottom surface of the liquid crystal panel20.

The backlight unit 10 is disposed below the liquid crystal panel 20. Thebacklight unit 10 includes a bottom cover 100, a reflective sheet 300, alight source, for example, a plurality of light emitting diodes 400, aprinted circuit board 401, a light guide plate 200, and a plurality ofoptical sheets 500.

An upper portion of the bottom cover 100 is open. The bottom cover 100receives the light guide plate 200, the light emitting diodes 400, theprinted circuit board 401, the reflective sheet 300, and the opticalsheets 500 therein.

The reflective sheet 201 is disposed below the light guide plate 200. Inmore detail, the reflective sheet 300 is disposed between the lightguide plate 200 and a bottom surface of the bottom cover 100. Thereflective sheet 300 reflects the light upward as the light is outputdownward from the bottom surface of the light guide plate 200.

The light emitting diodes 400 serve as a light source for generating thelight. The light emitting diodes 400 are disposed at one side of thelight guide plate 200. The light generated from the light emittingdiodes 400 is incident into the light guide plate 200 through the sideof the light guide plate 200.

The light emitting diodes 400 may include a blue light emitting diodegenerating the blue light or a UV light emitting diode generating the UVlight. In detail, the light emitting diodes 400 may emit the blue lighthaving the wavelength in the range of about 430 nm to about 470 nm orthe UV light having the a wavelength in the range of about 300 nm toabut 400 nm.

The light emitting diodes 400 are mounted on the printed circuit board401. The light emitting diodes 400 may be disposed under the printedcircuit board 401. The light emitting diodes 400 are driven by receivinga driving signal through the printed circuit board 401.

The printed circuit board 401 is electrically connected to the lightemitting diodes 400. The printed circuit board 401 may mount the lightemitting diodes 400 thereon. The printed circuit board 401 is disposedin the bottom cover 100.

The light guide plate 200 is disposed in the bottom cover 100. The lightguide plate 200 is disposed on the reflective sheet 100. The light guideplate 200 supplies light received from the light emitting diode 300upward by reflecting, refracting and scattering the light.

The light guide plate 200 is disposed below the liquid crystal panel200. The light guide plate 200 is disposed on the reflective sheet 300.The light guide plate 200 has a plate shape. The light guide plate 200is transparent. For example, a material used for the light guide plate200 may include an acrylic resin formed by methyl acrylate, ethylacrylate, cyclohexyl acrylate, or benzene acrylate. For example, a guidepart 210 may include polymer such as polymethylmethaacrylate (PMMA) orpolycarbonate (PC). The light guide plate 200 may include glass. Indetail, the glass used for the light guide plate 200 may include siliconoxide (SiO2), titanum oxide (TiO2), aluminum hydroxide (Al(OH)3), orZinc oxide (ZnO). The light guide plate 200 may have a thickness in therange of about 0.5 mm to about 1.5 mm.

As shown in FIGS. 2 to 4, a plurality of scattering parts 210 is formedon the light guide plate 200. That is, the scattering parts 210 areformed on at least one surface of the light guide plate 200. Thescattering parts 210 may change a path of incident light. That is, thescattering parts 210 may serve as a light path changing part forchanging the path of the incident light. In detail, the scattering parts210 may scatter the incident light. In more detail, the scattering parts210 may scatter the incident light upward. The scattering parts 210configure a scattered pattern on a top surface of the light guide plate200.

The scattering parts 210 may be disposed on the top surface of the lightguide plate 200. The scattering parts 210 may include protrusions whichare formed on the top surface of the light guide plate 200. Thescattering parts 210 may have a dot shape when viewed from a top side.

A diameter R1 of each of scattering parts 210 may be equal to or greaterthan about 90 μm. The diameter R1 of each scattering part 210 may be inthe range of about 90 μm to about 300 μm. In detail, the diameter R1 ofeach scattering part 210 may be in the range of about 100 μm to about300 μm. In more detail, the diameter R1 of each scattering part 210 maybe in the range of about 150 μm to about 250 μm.

The scattering parts 210 are spaced apart from each other. In this case,a pitch P between the scattering parts 210 may be gradually reduced asthe scattering parts 210 are located away from the light emitting diodes400. That is, the scattering parts 210 may be densely disposed as thescattering parts 210 are located away from the light emitting diodes400. Accordingly, the light guide plate 200 may uniformly supply lightupward.

The scattering part 210 includes a scattering protrusion 211 and ascattering groove 212.

The scattering protrusion 211 may include a curved surface. A protrudingpart of the scattering protrusion 211 may have a curved surface as awhole. In detail, the scattering protrusion may have a semisphere shape.A diameter R2 of the scattering protrusion 211 may be in the range ofabout 80 μm to about 290 μm. A height of the scattering protrusion 211may be in the range of about 40 μm to about 150 μm.

The scattering groove 212 may be formed on the top surface of the lightguide plate 200. The scattering groove 212 may be adjacent to thescattering protrusion 211. In detail, the scattering groove 212 maysurround the scattering protrusion 211. The scattering groove 212 mayextend around the scattering protrusion 211. The scattering groove 212may have a closed loop shape when viewed from the top side.

A width of each of the grooves 220 may be in the range of about 5 μm toabout 10 μm. A depth of each of the grooves 220 may be in the range ofabout 2 μm to about 6 μm.

As shown in FIG. 5, the scattering parts 210 may be provided on a bottomsurface of the light guide plate 200. That is, the scattering parts 210may directly face the reflective sheet 300.

As shown in FIG. 6, the scattering parts 210 may be provided on both oftop and bottom surfaces of the light guide plate 200.

As shown in FIGS. 7 and 8, a plurality of print scattering parts 220 maybe provided in the light guide plate 200. The print scattering parts 220may be printed on the top surface and/or the bottom surface of the lightguide plate 200.

The print scattering parts 220 may directly provided on the top surfaceand/or the bottom surface of the light guide plate 200. The printscattering parts 220 may be a pattern protruding from at least onesurface of the light guide plate 200, for example, the top surfaceand/or the bottom surface of the light guide plate 200. A diameter R3 ofeach of the print scattering parts 220 may be in the range of about 90μm to about 300 μm. In detail, the diameter R3 of each of the printscattering parts 220 may be in the range of about 100 μm to about 300μm. In more detail, the diameter R3 of each of the print scatteringparts 220 may be in the range of about 150 μm to about 250 μm.

The print scattering parts 220 include a plurality of beads 221 and aprinting part 222. The beads 221 may be transparent. The beads 221 may ahigh refractive index. The refractive index of the beads 221 may be inthe range of about 1.6 to 2.2. The beads 221 may include aluminum oxide(Al2O3) or titanium oxide (TiO).

A diameter of each of the beads 221 may be in the range of about 50 nmto about 10 μm. In detail, the diameter of each of the beads 221 may bein the range of about 5 μm to about 10 μm.

The printing part 222 includes a transparent resin. The printing part222 receives the beads 221. The beads 221 may be inserted into theprinting part 222. The printing part 22 may bond the beads 22 to the topsurface or the bottom surface of the light guide plate 200. The printingpart 222 may have a relatively high refractive index. A refractive indexof the printing part 222 may be in the range of 1.2 to 1.4.

If the print scattering part 220 is farther away from the light emittingdiode 400, an area of each printing scattering part 220 may gradually beincreased. That is, as the print scattering part 220 is farther awayfrom the light emitting diode 400, the area of each printing scatteringpart 220 may gradually be increased. Accordingly, the print scatteringpart 220 is farther away from the light emitting diode 400, so reductionin intensity of the light may be compensated.

The optical sheets 500 are disposed on the light guide plate 200. Theoptical sheets 500 change or improve characteristics of light outputfrom the top surface of the light guide plate 200 to supply the light tothe liquid crystal panel 20.

The optical sheets 500 may include a light conversion sheet 501, adiffusion sheet 502, a first prism sheet 503, and a second prism sheet504.

The light conversion sheet 501 may be disposed on a light path betweenthe light source and the liquid crystal panel 20. For example, the lightconversion sheet 501 may be disposed on the light guide plate 200. Indetail, the light conversion sheet 501 may be interposed between thelight guide plate 200 and the diffusion sheet 502. The light conversionsheet 501 may convert wavelength of incident light and supply theconverted light upward.

For example, when the light emitting diodes 400 are blue light emittingdiodes, the light conversion sheet 501 may convert blue light suppliedupward from the light guide plate 200 into green light and red light.That is, the light conversion sheet 501 may convert a part of the bluelight into green light having a wavelength in the range of about 520 nmto about 560 nm, and convert another part of the blue light into redlight having a wavelength in the range of about 630 nm to about 660 nm.

When the light emitting diodes 400 are UV light emitting diodes, thelight conversion sheet 501 may convert UV ray output from the topsurface of the light guide plate 200 into blue light, green light, andred light. The light conversion sheet 501 may convert a part of the UVray into blue light having a wavelength in the range of about 430 nm toabout 470 nm, and convert another part of the UV ray into green lighthaving a wavelength in the range of about 520 nm to about 560 nm, andconvert a still another part of the UV ray into red light having awavelength in the range of about 630 nm to about 660 nm.

Accordingly, light passing through the light conversion sheet 510 whichis not converted and light converted by the light conversion sheet 501form white light. That is, the blue light, the green light, and the redlight are combined with each other so that the white light may beincident to the liquid crystal panel 20.

As shown in FIGS. 9 and 10, the light conversion sheet 501 includes alower substrate 510, an upper substrate 520, a light conversion layer530, a lower reflection preventing layer 540, and an upper reflectionpreventing layer 550.

The lower substrate 510 is disposed below the light conversion layer530. The lower substrate 510 may be transparent and flexible. The lowersubstrate 510 may adhere to a bottom surface of the light conversionlayer 530.

For example, a material use for the lower substrate 510 may includetransparent polymer such as polyethyleneterephthalate (PET).

The upper substrate 520 is disposed on the light conversion layer 530.The upper substrate 520 may be transparent and flexible. The uppersubstrate 520 may adhere to the top surface of the light conversionlayer 530.

For example, a material used for the upper substrate 520 may includetransparent polymer such as PET.

The light conversion layer 530 is sandwiched between the lower substrate510 and the upper substrate 520. The lower substrate 510 and the uppersubstrate 520 support the light conversion layer 530. The lowersubstrate 510 and the upper substrate 520 protect the light conversionlayer 530 from external physical impact.

The lower substrate 510 and the upper substrate 520 have low oxygenpermeability and low moisture permeability. Thus, the lower substrate510 and the upper substrate 520 can protect the light conversion layer530 from external chemical impact by moisture and/or oxygen.

The light conversion layer 530 is interposed between the lower and uppersubstrates 510 and 520. The light conversion layer 530 may adhere to thetop surface of the lower substrate 510, and adhere to the bottom surfaceof the upper substrate 520.

The light conversion layer 530 includes a plurality of light conversionparticles 531 and a host layer 532.

The light conversion particles 531 are interposed between the lower andupper substrates 510 and 520. In more detail, the light conversionparticles 531 are uniformly distributed in the host layer 532, and thehost layer 532 is interposed between the lower substrate 510 and theupper substrate 520.

The light conversion particles 531 convert a wavelength of the lightemitted from the light emitting diodes 400. In detail, the lightconversion particles 531 receive light emitted from the light emittingdiodes 400 to convert the a wavelength of the incident light. Forinstance, the light conversion particles 531 may convert the blue lightemitted from the light emitting diodes 400 into the green light and thered light. That is, a part of the light conversion particles 531 mayconvert the blue light into green light having a wavelength in the rangeof about 520 nm to about 560 nm, and another part of the lightconversion particles 531 may convert the blue light into red lighthaving a wavelength in the range of about 630 nm to about 660 nm.

In addition, the light conversion particles 531 may convert the UV rayemitted from the light emitting diodes 400 into the blue light, thegreen light, and the red light. That is, a part of the light conversionparticles 531 may convert the UV ray into blue light having a wavelengthin the range of about 430 nm to about 470 nm, and another part of thelight conversion particles 531 may convert the UV ray into green lighthaving a wavelength in the range of about 520 nm to about 560 nm. Stillanother part of the light conversion particles 531 may convert the UVray into red light having a wavelength in the range of about 630 nm toabout 660 nm.

That is, when the light emitting diodes 400 are a blue light emittingdiode 400 for generating blue light, light conversion particles 531 forconverting the blue light into green light and red light, respectivelymay be used. In addition, when the light emitting diodes 400 are a bluelight emitting diode 400 for generating the UV ray, light conversionparticles 531 for converting the UV ray into blue light, green light,and red light, respectively may be used.

The light conversion particles 531 may include a plurality of quantumdots (QD). The quantum dots may include core nano-crystals and shellnano-crystals surrounding the core nano-crystals. In addition, thequantum dots may include organic ligands bonded to the shellnano-crystals. Further, the quantum dots may include an organic coatinglayer surrounding the shell nano-crystals.

The shell nano-crystals may be prepared as at least two layers. Theshell nano-crystals are formed on the surface of the core nano-crystals.The quantum dots lengthen a wavelength of the light incident into thecore nano-crystals by using the shell nano-crystals forming a shelllayer, thereby improving the light efficiency.

The quantum dots may include at least one of a group-II compoundsemiconductor, a group-III compound semiconductor, a group-V compoundsemiconductor, and a group-VI compound semiconductor. In more detail,the core nano-crystals may include CdSe, InGaP, CdTe, CdS, ZnSe, ZnTe,ZnS, HgTe or HgS. In addition, the shell nano-crystals may includeCuZnS, CdSe, CdTe, CdS, ZnSe, ZnTe, ZnS, HgTe or HgS. The quantum dotmay have a diameter of about 1 nm to about 10 nm.

The wavelength of the light emitted from the quantum dots can beadjusted according to the size of the quantum dots. The organic ligandmay include pyridine, mercapto alcohol, thiol, phosphine and phosphineoxide. The organic ligand may stabilize the unstable quantum dots afterthe synthesis process. Dangling bonds may be formed at the valence bandand the quantum dots may be unstable due to the dangling bonds. However,since one end of the organic ligand is the non-bonding state, the oneend of the organic ligand is bonded with the dangling bonds, therebystabilizing the quantum dots.

In particular, if the size of the quantum dot is smaller than the Bohrradius of an exciton, which consists of an electron and a hole excitedby light and electricity, the quantum confinement effect may occur, sothat the quantum dot may have the discrete energy level. Thus, the sizeof the energy gap is changed. In addition, the charges are confinedwithin the quantum dot, so that the light emitting efficiency can beimproved.

Different from general fluorescent pigments, the fluorescent awavelength of the quantum dot may vary depending on the size of theparticles. In detail, the light has the shorter a wavelength as the sizeof the particle is reduced, so that the fluorescent light having thewavelength band of visible ray can be generated by adjusting the size ofthe particles. In addition, the quantum dot represents the extinctioncoefficient which is 100 to 1000 times higher than that of the generalpigment and has the superior quantum yield as compared with the generalpigment, so that strong fluorescent light can be generated.

The quantum dots can be synthesized through the chemical wet scheme. Thechemical wet scheme is to grow the particles by immersing the precursormaterial in the organic solvent. According to the chemical wet scheme,the quantum dots can be synthesized.

The host layer 532 surrounds the light conversion particles 531. Thatis, the light conversion particles 531 are uniformly distributed in thehost layer 532. The host layer 531 may include a polymer. The host layer532 is transparent. That is, the host layer 532 may be formed by using atransparent polymer.

The host layer 532 is interposed between the lower and upper substrates510 and 520. The host layer 532 may adhere to the top surface of thelower substrate 510 and the bottom surface of the upper substrate 520.

The sealing part 540 is disposed at the side of the light conversionlayer 530. In detail, the sealing part 540 covers the side of the lightconversion layer 530. In more detail, the sealing part 540 can also bedisposed at the sides of the lower substrate 510 and the upper substrate520. In this case, the sealing part 540 covers the sides of the lowersubstrate 510 and the upper substrate 520.

In addition, the sealing part 540 may be bonded to the sides of thelight conversion layer 530, the lower substrate 510 and the uppersubstrate 520. In addition, the sealing part 540 may closely adhere tothe sides of the light conversion layer 530, the lower substrate 510 andthe upper substrate 520.

Therefore, the sealing part 540 can seal the side of the wavelengthconversion layer 530. That is, the sealing part 540 may serve as aprotective part for protecting the wavelength conversion layer 530 fromthe external chemical impact.

The liquid crystal panel 20 is disposed on the optical sheets 500. Inaddition, the liquid crystal panel 20 is disposed on the panel guide 23.The liquid crystal panel 20 may be guided by the panel guide 23.

The liquid crystal panel 20 displays images by adjusting intensity oflight passing through the liquid crystal panel 20. In detail, the liquidcrystal panel 20 is a display panel for displaying the images by usingthe light emitted from the backlight unit 10. The liquid crystal panel20 includes a TFT substrate 21, a color filter substrate 22 and a liquidcrystal layer interposed between the two substrates. In addition, theliquid crystal panel 20 includes polarizing filters.

Hereinafter, the TFT substrate 21 and the color filter substrate 22 willbe described in detail although they are not shown in the drawings indetail. The TFT substrate 21 includes a plurality of gate lines and aplurality of data lines crossing the gate lines to define pixels and athin film transistor (TFT) is provided at each cross section such thatthe thin film transistor TFT can be connected to a pixel electrode ofthe pixel in one-to-one correspondence. The color filter substrate 22includes color filters having R, G and B colors corresponding to thepixels, a black matrix covering the gate lines, data lines and thin filmtransistors within the limit of the color filters, and a commonelectrode covering the above elements.

A driving PCB 25 is provided at an outer peripheral portion of theliquid crystal panel 210 to supply driving signals to the gate lines anddata lines.

The driving PCB 25 is electrically connected to the liquid crystal panel20 by a COF (chip on film) 24. The COF 24 may be replaced with a TCP(tape carrier package).

As described above, the liquid crystal display according to theembodiment disposes the light conversion member on the light guide plate200 and the scattering parts 210 has a large diameter in the range ofabout 90 μm to about 300 μm. In this case, the light conversion memberincludes the light conversion particles. The light conversion particlesmay randomly change a light path while convert a wavelength of incidentlight. That is, the light conversion particles may also perform ascattering function.

Accordingly, even if the scattering parts 210 have a large diameter,because the light conversion member has the scattering function, thewhole brightness uniformity is not reduced.

Therefore, the scattering parts 210 have a large diameter so that thewhole brightness may be increased.

As a result, the display device according to the embodiment canrepresent improved brightness without reducing brightness uniformity.

Any reference in this specification to “one embodiment,” “anembodiment,” “example embodiment,” etc., means that a particularfeature, structure, or characteristic described in connection with theembodiment is included in at least one embodiment of the invention. Theappearances of such phrases in various places in the specification arenot necessarily all referring to the same embodiment. Further, when aparticular feature, structure, or characteristic is described inconnection with any embodiment, it is submitted that it is within thepurview of one skilled in the art to effect such feature, structure, orcharacteristic in connection with other ones of the embodiments.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments can be devised by those skilled inthe art that will fall within the spirit and scope of the principles ofthis disclosure. More particularly, various variations and modificationsare possible in the component parts and/or arrangements of the subjectcombination arrangement within the scope of the disclosure, the drawingsand the appended claims. In addition to variations and modifications inthe component parts and/or arrangements, alternative uses will also beapparent to those skilled in the art.

Experimental Example

A light conversion sheet including a CdSe/ZnS quantum dot having adiameter of about 2 nm was disposed on a top surface of a light guideplate in which scattering parts having a diameter of about 150 μm wereprovided, and then light was emitted to a side of the light guide plateusing a blue light emitting diode.

Comparative Example

Comparative Example is similar to Experimental Example except that thescattering parts having a diameter of about 25 μm were provided on thelight guide plate.

Result

Brightness uniformity of the Experimental Example is substantially thesame as that of the Comparative Example and brightness of theExperimental Example was improved by about 2% as compared with that ofthe Comparative Example.

The invention claimed is:
 1. A display device comprising: a lightsource; a light guide part having a plate shape with a side surface anda top surface to guide light received from the light source at the sidesurface such that the light exits through the top surface of the lightguide part; a scattering part to scatter light exiting from the topsurface of the light guide part; a light conversion member provided overthe light guide part and the scattering part, the scattering part beingprovided between the light guide part and the light conversion member;and a display panel over the light conversion member, wherein thescattering part is provided over the top surface of the light guidepart, the scattering part including a plurality of beads, and the beadshaving a diameter in a range of 50 nm to 10 μm, the light conversionmember includes a lower substrate, a light conversion layer on the lowersubstrate, and an upper substrate on the light conversion layer, thelight conversion layer has a plurality of light conversion particles anda host layer, and the light conversion particles comprise a quantum dot(QD), and the beads are provided between the lower substrate of thelight conversion member and the top surface of light guide part.
 2. Thedisplay device of claim 1, wherein the scattering part includes at leastone printed part, the beads being provided in the at least one printedpart.
 3. The display device of claim 1, wherein the scattering partinclude patterns based on a plurality of printed parts made from atransparent resin, the beads being dispersed inside the plurality ofprinted parts.
 4. The display device of claim 3, wherein the pluralityof printed parts have a diameter in a range of 90 to 300 micrometers. 5.The display device of claim 1, wherein the beads have a refractive indexwhich is higher than a refractive index than the light guide part. 6.The display device of claim 1, wherein the refractive index of the beadsis in a range of 1.6 to 2.2.
 7. The display device of claim 1, wherein arefractive index of the light guide part is in a range of 1.2 to 1.4. 8.The display device of claim 1, wherein the light source is provided on abottom side of the light guide part.
 9. The display device of claim 1,wherein the bead is transparent.
 10. The display device of claim 2,wherein a refractive index of the beads and the at least one printedpart is different from each other.
 11. The display device of claim 1,wherein a refractive index of the beads is different from a refractiveindex of the light guide part.